This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.
In recent years smart capsules, which once ingested can perform endoscopy and biopsy, have been the focus of intense research and development. Included in this class of capsules is an endoscopic smart capsule used by gastroenterologists to collect images from hard-to-reach areas in the gastrointestinal (GI) tract (in particular the small intestine which cannot be reached via standard endoscopic methods, including colonoscopy). Pharmaceutical companies have also been interested in similar technologies for releasing medications at specific sites in the GI tract. Site-specific delivery can optimize the therapeutic efficacy of many drugs with preferential absorption sites. Exemplary capsules in the prior art are used in the pharmaceutical industry for studying human drug absorption. This capsule incorporates a spring-loaded cylinder which, once actuated and released by an RF signal, pushes a piston and forces the drug formulation out through a small hole. The location of the capsule is monitored through gamma ray scintillation imaging by incorporating a small amount of radioactive material in capsule. Other similar efforts in this area include a radiofrequency activated capsule relying on a shape-memory alloy actuator to rotate a cylinder and align a series of holes, allowing the drug to be released from a reservoir (location tracking was accomplished by x-ray fluoroscopy). Still other efforts include systems based on electrolytic actuation (gas production) or solid fuel micro-thrusters with the former being too slow for most practical applications and the latter posing safety issues related to high temperatures and pressures generated within the device.
Magnetically actuated capsules have also been investigated wherein a capsule which contracts or collapses under magnetic attraction to realize a multimodal drug release. In addition, a similar capsule made up of magnetic semi-hard and soft materials which disintegrates upon a demagnetization process is also known.
Although suitable for drug absorption studies in clinical-settings, the abovementioned approaches cannot be used for actual therapy in larger populations that can benefit from smart capsules which release the drug at an optimum location in the GI tract. This is mainly due to the problems associated with the need for real-time tracking of the capsule location (using either gamma rays or fluoroscopy both of which are not practical in a non-clinical setting and pose health hazards if used repeatedly). In addition, all these systems require active participation by the patient/volunteer or investigator in the form of triggering an RF transmitter once the capsule is in the targeted position. Such requirement is very difficult to enforce and/or guarantee (the capsule might reach the desired location in the middle of the night or at a time untimely for the required triggering).
There is, therefore an unmet need for a novel smart capsule capable of drug delivery to a selective location in the GI tract without the need for monitoring of the capsule's location in the tract.